1. Field of the Invention
The invention relates to a piston for a piston-cylinder unit.
2. Description of the Related Art
A prior art piston for a piston-cylinder unit is disclosed in DE 44 10 996 C1. This prior art piston comprises a piston body having passages which connect two spaces on either side of the piston filled with a medium, wherein the passages are covered by at least one disk which is centered relative to the center of the piston by a centering sleeve during assembly.
In the part of the description relating to variants V1 and V2, it is noted that the centering of the valve disks and the spring disk(s) during assembly is a problem worthy of consideration. In variant V1, a centering sleeve is used to position the disk springs during assembly, because the ring 39 located at the inner diameter, which centers the disk when the piston is in the assembled state, cannot assume a centering function when the disk springs are not in a pretensioned state. The height of the disk springs when they are not pretensioned is greater than that of the ring 39. The centering sleeve is an additional tool which must be removed after the piston is assembled.
In variant V4, an angle ring is used. An angle ring of this kind with the required tolerances is produced by cutting and not by stamping techniques. Cutting operations are more expensive than stamping. Therefore, the angle ring is expensive to produce.